Identification and characterization of circulating and adipose tissue infiltrated CD20+ T cells from subjects with obesity that undergo bariatric surgery

T cells play critical roles in adipose tissue (AT) inflammation. The role of CD20⁺ T cell in AT dysfunction and their contributing to insulin resistance (IR) and type 2 diabetes progression, is not known. The aim was to characterize CD20⁺ T cells in omental (OAT), subcutaneous (SAT) and peripheral blood (PB) from subjects with obesity (OB, n = 42), by flow cytometry. Eight subjects were evaluated before (T1) and 12 months post (T2) bariatric/metabolic surgery (BMS). PB from subjects without obesity (nOB, n = 12) was also collected. Higher percentage of CD20⁺ T cells was observed in OAT, compared to PB or SAT, in OB-T1. CD20 expression by PB CD4⁺ T cells was inversely correlated with adiposity markers, while follicular-like CD20⁺ T cells were positively correlated with impaired glucose tolerance (increased HbA1c). Notably, among OB-T1, IR establishment was marked by a lower percentage and absolute number of PB CD20⁺ T cells, compared nOB. Obesity was associated with higher percentage of activated CD20⁺ T cells; however, OAT-infiltrated CD20⁺ T cells from OB-T1 with diabetes displayed the lowest activation. CD20⁺ T cells infiltrating OAT from OB-T1 displayed a phenotype towards IFN-γ-producing Th1 and Tc1 cells. After BMS, the percentage of PB CD4⁺CD20⁺ T cells increased, with reduced Th1 and increased Th17 phenotype. Whereas in OAT the percentage of CD20⁺ T cells with Th1/17 and Tc1/17 phenotypes increased. Interestingly, OAT from OB pre/post BMS maintained higher frequency of effector memory CD20⁺ T cells. In conclusion, CD20⁺ T cells may play a prominent role in obesity-related AT inflammation.